DEUTSCHNEUDORF, Germany -- Treasure hunters in Germany say they have detected a cavern they believe holds stolen Russian artifacts and Nazi gold hidden since World War II.

The team thinks the man-made cavern about 65 feet underground near the village of Deutschneudorf on the German-Czech Republic border holds the so-called Amber Room, an 18th-century chamber decoration the Nazis stole from the Soviet Union during the war, Spiegel Online reported Tuesday.

They claim to have detected about two tons of gold last weekend using electromagnetic pulse measurements, though they have yet to verify it, the German magazine reported.

"I'm well over 90 percent sure we have found the Amber Room," Deutschneudorf Mayor Heinz-Peter Haustein, who led the search, told Spiegel Online. "The chamber is likely to be part of a labyrinth of storage rooms that the Nazis built here."

Haustein, 53, who has searched for the long-lost treasure for a decade, said it will probably take until Easter to reach the chamber because diggers have to make sure there are no booby traps.

"This has got too risky for us to do it alone. There could be mines down there," he said, adding that regional authorities had agreed to help with the excavation.